Laser diode absorption spectroscopy for accurate CO_(2) line parameters at 2(mu)m: consequences for space-based DIAL measurements and potential biases

摘要

Space-based active sensing of CO_(2) concentration is a very promising technique for the derivation of CO_(2) surface fluxes. There is a need for accurate spectroscopic parameters to enable accurate space-based measurements to address global climatic issues. New spectroscopic measurements using laser diode absorption spectroscopy are presented for the preselected R30 CO_(2) absorption line ((20~(0)1)_(III)<-(000) band) and four others. The line strength, air-broadening halfwidth, and its temperature dependence have been investigated. The results exhibit significant improvement for the R30 CO_(2) absorption line: 0.4percent on the line strength, 0.15percent on the air-broadening coefficient, and 0.45percent on its temperature dependence. Analysis of potential biases of space-based DIAL CO_(2) mixing ratio measurements associated to spectroscopic parameter uncertainties are presented.